1. Field of the Invention
This invention relates to an improved finned heat exchanger tube and more particularly to a tube configuration that affords uniform distribution of liquid over the exterior surface of the finned tube.
2. Description of the Prior Art
Typifying an environment in which a finned heat exchanger tube is employed is that disclosed in U.S. Pat. No. 3,180,405 to Hinde, which includes a condenser wherein a plurality of horizontally extending tubes are disposed in vertically aligned rows to from an array over which a liquid flows. A fluid is circulated inside the tubes and such fluid is at a temperature different from that of liquid flowing over the exterior of the tubes so that heat energy is exchanged between the internal fluid and the external liquid.
U.S. Pat. No. 3,523,577 to Milton discloses in FIG. 7 a finned tube configuration that is widely available and widely used in heat exchanger environments.
U.S. Pat. No. 3,025,685 to Whitlow discloses a finned tube wherein the fins are closely spaced to one another so that the grooves between adjacent fins causes liquid introduced into the grooves to be distributed circumferentially of the grooves by capillary action. The '685 patent also discloses a longitudinally disposed groove that traverses the circumferential grooves; the longitudinally disposed groove causes the liquid to move axially from one capillary groove to the next adjacent one so that liquid is spread axially and circumferentially throughout the entire finned surface by means of capillary action. The structure of the '685 patent performs adequately for relatively low feed rates of the liquid wetting the outer surface of the tube and for relatively small tubes. Because the patented structure relies on capillary action to wet the tube, however, it provides little or no improvement at high flow rates, especially in large heat exchangers and relatively large diameter tubes of one or more inches in diameter.
U.S. Pat. No. 2,896,426 discloses a finned heat exchanger tube which is vertically disposed when in operation. Each one of the fins has a radially extending slit so that fluid applied to the upper fins can gravitate downward through the slits to lower fins.